Highly Selective Electrochemical Detection of Vitamin K1 (Phylloquinone) in Simulated Blood Serum Using Bimetallic Cu/Ni-MOF Decorated CNT Composite on Nickel Foam.

Abstract

Phylloquinone (Vitamin K) is a vital vitamin for humans since it plays a critical role in blood clotting by enabling the synthesis of proteins required for coagulation. The physiological and therapeutic significance of Vitamin K (VIT K) necessitates the development of precise techniques for its accurate quantification. In this study, we report the electrochemical detection of Vitamin K in simulated blood serum using a bimetallic CuNi-MOF/CNT (copper/nickel metal-organic framework decorated carbon nanotube) composite on nickel foam (NF) via differential pulse voltammetry (DPV). The CuNi-MOF/CNT composite is synthesized using a one-pot solvothermal method, embedding Cu/Ni-MOF with CNTs to form a porous structure with enhanced electrical properties. Scanning electron microscopy (SEM) reveals the presence of bimetallic MOFs with granular and cubical morphologies along with well-dispersed CNT structures; Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirm functional group interactions and crystallinity of the CuNi-MOF/CNT composite. The CuNi-MOF/CNT composite, drop-casted (0.5 wt %) on a Ni foam electrode, exhibits excellent electrochemical performance with a wide linear detection range from 30 nM to 10 μM, a high sensitivity of 1.97 mA μM^-1 cm^-2, and a low detection limit (LOD) of 0.03 nM. The sensor displays commendable selectivity, as it maintains its activity even when it is subjected to potentially interfering species like DA, AA, UA, and H₂O₂. The composite demonstrates excellent stability and reproducibility (tested using four electrodes). The superior performance of the sensor can be ascribed to the synergistic effect of the bimetallic Cu/Ni-MOF and CNTs, which enhances electron transfer, increases surface area, and improves conductivity. The unique structural and electronic properties of the composite contribute to the enhanced electrocatalytic activity, demonstrating its potential for advanced biosensing applications in clinical diagnostics and next-generation wearable health monitoring systems.